During a two‐year period, 363 women with postmenopausal bleeding were studied. Included were women in whom the menses had been absent for one or more years and women treated with exogenous estrogens for at least one year. Endometrial tissue obtained by curettage was found to be hyperplastic (sometimes malignant) in a third of the cases, atrophic in a third, and proliferative in a third. Mechanisms of bleeding and sources of endogenous estrogens in postmenopausal women are discussed, as is the subject of steroidogenesis in patients unusually susceptible to endometrial carcinoma. In women with obesity, diabetes, or liver disease there is either an increased production rate of Δ4‐androstenedione or increased conversion of this hormone to estrone. The management of postmenopausal bleeding is discussed. The role of progesterone in preventing hyperplastic changes in the endometrium is emphasized. It is recommended that, during the climacteric, women receiving estrogen therapy and even those who are not, should be given progestogen for several cycles to see if withdrawal bleeding can be induced. If such bleeding does not occur, then progestogen therapy should be discontinued.